Abstract: An original image of a target is provided. The original image is guidedly perturbed into a first plurality of recognizable uniquely perturbed images, each of the first plurality of recognizable uniquely perturbed images being recognizable as representing the target and distinguishable from the original image. The first plurality of recognizable uniquely perturbed images is guidedly perturbed into a second plurality of unrecognizable uniquely perturbed images, each of the second plurality of unrecognizable uniquely perturbed images being unrecognizable as representing the target. A contour is generated between the first plurality of recognizable uniquely perturbed images and the second plurality of unrecognizable uniquely perturbed images.

Abstract: A method and apparatus for extracting an object from an image, in which one locates a pixel within the image (the "central" pixel), and then sequentially compares the brightness of neighboring pixels, proceeding outward from the central pixel. In so doing, one determines the largest dropoffs in brightness between neighboring pixels, and uses these to determine a brightness threshold for extracting pixels belonging to the object. In a preferred embodiment, one determines the threshold by comparing the largest dropoffs, identifies overlapping regions of brightness level common to all the dropoffs, and sets the threshold at the midpoint of the common overlapping region.